Certain printed circuit boards may include planar magnetic cores. The planar magnetic cores may interact with elements of the printed circuit boards, such as conductive traces, to form transformers, inductors, or other circuit elements. Planar magnetic cores may be assembled by adhering portions of the magnetic core to the printed circuit board. Since electrical characteristics of each planar magnetic core may depend upon physical characteristics (e.g., alignment and spacing) of the planar magnetic core, assembling planar magnetic cores by hand can be time consuming and prone to defects.